The Department of Energy (DOE) is in the process of decontamination and decommissioning (D&D) many of its nuclear facilities throughout the United States. These facilities are typically chemically or radiologically contaminated. For instance, within the next few decades, millions of cubic meters of bulk building material, such as concrete, brick, and mortar, will be removed from nuclear facilities across the United States as a result of these decontamination and decommissioning activities. Material that has been exposed to radiological or chemical contamination must undergo an expensive treatment or disposal process. Not all of the decommissioned material is contaminated. Thus, segregating the contaminated material from the “clean” material can significantly reduce D&D costs and expenses. In order to segregate the contaminated material from the clean material, some form of analysis or “characterization” is performed to determine the extent and amount of contamination at any given facility.
If the radiological history indicates that a particular facility or structure may have been exposed to radiation or chemical contaminants, an analysis should be conducted to determine if the building materials contain residual radioactive or chemical material. For instance, if the concrete has been determined, through the radiological history, as not being radioactive and not containing residual radioactive material, then the concrete can be released or removed. However, if the radiological history will not support determination that the concrete does not contain residual radioactive material, then the property should be treated as either (1) known to be contaminated or previously contaminated or (2) possibly contaminated. In either case, a determination should be performed to determine the extent of the contamination. Concrete known to be either contaminated, previously contaminated, or possibly contaminated must be comprehensively surveyed before release to demonstrate compliance with release limits.
Since radiochemicals or chemicals on or in contaminated concrete are typically encapsulated in the complex building matrix, cost effective removal and disposal of the contaminated material fraction require techniques to penetrate the concrete to assess the levels of contamination within the matrix prior to the release of the material. If the concrete material is volumetrically contaminated, surface removal techniques may not provide adequate decontamination.
Currently, in order to determine volumetric contamination, cores are drilled from material, such as concrete. The concrete cores are shipped to certified laboratories where the concrete is run through a battery of tests to determine the extent of contaminants. However, in addition to delays, concrete boring often results in cross-contamination, which can lead to inaccurate results and increase the amount of waste generated. Additionally, some contaminants volatilizes out of the concrete. This volatilization can lead to air borne problems in the immediate vicinity of the core and additional cross contamination.
What is needed, therefore, is a method and apparatus which can quickly and accurately volumetrically characterize building materials, such as concrete, while minimizing cross-contamination and waste.